Spinning device



Feb. 4, 1958 w. R. KOCAY .SPINNING DEVICE Filed June 16, 1955 Y! m4 T6. 0 MK mm ATTORNEY.

United States atent W SPINNING DEVICE Witold R. Kocay, Stamford, Conn., assignor to American Cyanamid Company, New York, N. Y., a corporation of Maine Application June 16, 1955, Serial No. 515,911

2 Claims. (Cl. 18--8) This invention relates to a spinning device which is especially adapted for use in the production of artificial or synthetic filaments, and more particularly is concerned with a heated spinnerette header or heading (and the combination thereof with a spinnerette) for use in the production of filaments from a viscous spinning solution, e. g., a viscous solution of an acrylonitrile polymerization product. Still more particularly, the invention is concerned with such a device which is adapted to be immersed in a liquid coagulating bath, for instance, a cold (e. g., 15 C. to +10 C.) aqueous coagulating bath such as is used in certain processes of producing filaments comprised of a polymer or copolymer of acrylonitrile.

In producing artificial filaments by the spinning of solutions of a fiber-forming material, it frequently happens that the solution at normal temperature, or when warmed only slightly, is so viscous that it cannot be extruded or spun satisfactorily because, for example, of low pullaway speed from the face of the spinnerette and resulting low production rate per spinning unit. It would appear at first glance that a solution to this problem would reside in merely heating a large bulk of the spinning solution by suitable means prior to transmitting the solution to the spinnerette head. Although such technique might be useful in the case of those spinning solutions which do not undergo any appreciable viscosity or other changes on exposure to heat for a prolonged period, it is not practical in the case of those spinning solutions which are detrimentally affected, or objectionably altered in properties, upon heating for a relatively prolonged period of time, e. g., solutions of polymeric or copolymeric acrylonitrile. The problem is further aggravated when it is desired to lead the coagulated filaments or yarn out of the coagulating bath to further treating positions without passage over a submerged guide roller or rollers in order to obviate damage to the said filaments that frequently results when such rollers are used.

It was suggested prior to my invention that, in spinning artificial silk, there be used a spinnerette or die provided with means so arranged as to permit the circulation (either within or outside the spinnerette) of a liquid or gaseous fluid medium at a constant temperature, whereby both the spinnerette and the solution being extruded therethrough also are at a constant temperature (see British Patent No. 293,416). Also, in German Patent No. 542,890 there is disclosed a device for the electrical heating, prior to extrusion, of spinning solutions to be spun into synthetic fibers by a dry-spinning method. Various types of spinnerettes and spinnerette assemblies that are adapted to be submerged in a liquid coagulating bath also were known prior to my invention. Illustrative of such types are those shown in U. S. Patent No. 2,370,765.

It is an object of the present invention to provide a new and improved device for use in spinning viscous spinning solutions whereby a small volume of the solution is effectively, economically and rapidly heated immediately prior to extrusion of the solution through the holes or openings in the face at the spinnerette.

Another object of the invention is to provide a device by the use of which the speed at which newly formed filaments can be taken away from the face of the spinnerette is materially increased.

Another object of the invention is to provide a spinning device whereby the freshly extruded filaments can be directed upwardly (more particularly vertically upwardly) to a position outside the coagulating bath where they are subjected to further processing steps; and to effect such upward direction of the filaments without the aid of a submerged thread guide or roller.

Another object of the invention is to provide a spinning device which is compact, efficient, relatively inex pensive and simple to construct from readily available materials; and by the use of which synthetic, continuousfilament yarns or threads of improved quality can be produced (especially yarns or threads formed of a polymer or copolymer of acrylonitrile) since the freshly formed filaments are subjected to little, if any, tension prior to stretching.

Another object of the invention is to provide a spinning device which operates efliciently in a cold aqueous coagulating bath; and by the use of which the spinning operation as a whole is improved, the individual, freshly extruded filaments are more uniform in diameter, and, in general, an overall improvement in the uniformity of multi-filament yarns is obtained.

Other objects of the invention will be apparent to those skilled in the art from the accompanying drawing and the following description.

The novel features which are characteristic of my invention are set forth in the appended claims. The invention itself, however, will best be understood by reference to the following more detailed description when considered in connection with the accompanying drawing in which:

Fig. 1 is a side sectional view of apparatus embodying my invention;

Fig. 2 is a perspective view of apparatus embodying the invention and corresponding generally to that shown in Fig. l; and

Fig. 3 illustrates somewhat schematically the use of the apparatus in the wet-spinning of continuous-filament yarn.

Referring to the drawing, which is merely illustrative of devices embraced by my invention, it will be noted that the device there shown is a particular form of a spinnerette assembly 10 which is especially adapted to be immersed in a liquid (more particularly cold liquid) coagulating bath 12 contained in the vessel 14 (Fig. 3). This assembly includes a spinnerette 16 and a spinnerette header or heading 18. The header 18 comprises an elongated body member 20 which is provided with a central duct 22 for the passage of a viscous spinning solution (e. g., a solution of homopolymeric or copolymeric acrylonitrile dissolved in a concentrated aqueous solution of sodium thiocyanate) from a supply source (not shown). The elongated body member 20 and the walls defining the central duct 22 may be readily fabricated from any suitable material that will not either harmfully afiect or be harmfully aifected by, the spinning solution in contact therewith during use of the device. Thus, in certain cases, the body member 20 and the conduit for carrying the spinning solution to the spinnerette each may be formed of metallic tubing such, for example, as stainless steel tubing, glass tubing, etc.

Referring now more particularly to Fig. 1, it will be noted that the elongated body member 20 curves upwards, specifically vertically upwards, at its lower end 24 so as to permit the upward, more particularly vertically upward, extrusion of the spinning solution, as indicated at 26 in Figs. 1 and 3, The lower end 24 of the elongated body member terminates in a support 28 for the spinnerette 16. This support may be formed, for instance, by rigidly attaching, as by welding for example, a flange having a central aperture to the extreme lower end of the body member 20. The central aperture in the aforementioned flange is in alignment with the aperture or opening at the lower end of the duct 22, the former being at least as large in diameter as the latter, and advantageously in many cases is slightly larger in diameter than the latter.

The central duct 22 is surrounded by a hollow heating unit 30 which is defined by the side walls 32 and 34. The unit 30. is rigidly attached and sealed, advantageously by welding so that it is fixedly attached, to the duct 22 as shown by the union or weld 36.

Any suitable, means can be provided for circulating a hot fluid medium, e. g-., steam, hot water, hot oil, etc, through the hollow heating unit 30, and also for introducing a viscous spinning solution that is to be spun into a synthetic or artificial filament into the central duct 22. The means shown in the drawing are illustrative of how this can be accomplished and; constitute a preferred embodiment of the invention. Such means advantageously and preferably include, as shown in Fig. 1, a hot fluid inlet 38' in the lower end of the body member 20 close to its lower extremity for introducing a hot fluid medium to the hollow heating unit 30 and a fluid outlet 40 in the upper endof the aforesaid body member 20 close to its upper-extremity for withdrawing the said fluid medium from the said heating unit. Inlet conduit 42 provides means for introducing the hot fluid medium to the heating unit 30- through the inlet 38; while outlet conduit 44 provides means for withdrawing the fluid medium from the heating unit 30 through the outlet 40, The conduits 42 and 44 are formed of any suitable material which is inertto the hot fluid medium passing therethrough and, preferably also, a high heat conductivity, e. g., copper tubing.

Optimum results are obtained when the hot fluid inlet 38 is positioned as is shown in the drawing. However, the device is operative when this inlet is situated elsewhere along the wall 32 and on the opposite side from the wall having the fluid outlet 40. For instance, inlet 38 may be situated opposite the outlet 40.

As shown in Fig. 1, inlet conduit 42 is positioned closely to the elongated body member 20, and preferably is rigidly attached thereto, for instance, by welds such as those shown at 46, 48 50 and 52.

As also shown in the drawing, and in the preferred embodiment of the invention, the upper and lower ends of the elongated body member 20 are suitably spaced from each other, and are in the same vertical plane.

Coupling or union 54- provides a convenient means for attaching the duct 22 to a candle filter (not shown). in which the spinning solution is filtered before it passes to the device of the present invention.

Referring now more-particularly to the means shown in Fig. 1. for detachably mounting the spinnerette 16, face upwards, upon the support 28, the male threaded member 56-is fitted'so that at-lcastpart of theupper face thereof is in. contact: with the lower face of the spinnerette support 28. Threaded member- 56' advantageously is rigidly attached to thebottom. of the support 28 and to the lower endof the body member 29 by any suitable means, e. g., flanges, inserts, or asuitable adhesive which also is a heat'insulator, as shown at 57'. The spinnerette 16 isv mounted with theface upwards and with the lip 58 interposed between gaskets or washers 60 and 62 (formed, forexample, of, polymerized tetrafluoroethylene). Insert or packing 64 (formed, forinstance, of a molded; synthetic insulating material, e. g, polymerizeditetrafiuoroethylene) provides a tightsealbetween the sidewall of: the spinnerette and the internally threaded or female coupling 66. Male threaded member 56 and female coupling 66 may-be formed of anysuitable heatinsulating material, e. g., molded phenolic resin, nylon, polymerized tetrafluoroethylene, etc. By tightening the female coupling 66 upon the male threaded member 56, a rigid, leakproof joint or union is formed between the spinnerette 16 and the header 18. Furthermore, the arrangement provides a quick and convenient means for disconnecting the spinnerette for removal, inspection and/ or replacement when deemed necessary to do so.

As shown in the drawing a jacket of heat-insulating material surrounds the elongated body member 20 and those parts of the conduits 42 and 44 that are adjacent to the said body member. This jacket of insulating material may comprise, for instance, a main layer 63 of heat insulation, e. g., foam glass, sheet cork, various synthetic resins (e. g., polystyrene, phenolic resins, urea resins, etc.) in foamed or cellular form, sheet asbestos, glass wool, rock wool, balsam wool, cellular gypsum, etc. The layer 68 of insulation, which advantageously is foam glass or a foamed synthetic resin, is covered by a protective layer 70 that may take the form of an ad'- hesive tape of cotton, nylon, linen, glass fibers, or one made from fibers of an acryl'onitri le polymer, etc. Outer layer 72 is preferably one which effectively seals layers 68 and 70 against the entrance of moisture (and/ or other liquids with which said layers otherwise might come in contact, such as the liquid of which the coagulating bath is composed), and adds strength to the unit. For instance, layer 72 may comprise or be composed of a synthetic resin such as a phenolic resin, an epoxy resin, nylon, etc. It may be applied by any suitable means depending upon its characteristics, for instance, by impregnating and coating the layer 70 (after it is in place) with the liquid resin (or a solution thereof) and hardening the resin in, situ by known means.

Fig. 3 shows a preferred application of the spinning device of the present invention. This view shows the spinnerette assembly, held in' positionby the support 74, and immersed in the liquid coagulating bath-12. The extruded filaments are directed upwards as shown at 26-, and the thread 76. of gelled filaments is collected on the spaced apart, converging upperroll 78- and lower roll 80- uponwhich they advance while they are further treated, e. g., washed, and thereafter are further processed, c. g., stretched, dried, heat-relaxed, etc.

The spinning device or assembly of this invention accomplishes the Objects ofthe invention, including those specifically set forth hereinbefore. it provides a compact, eflicient, relatively simple and inexpensive spinning unit whereby a spinning solution can be raised to a desired temperature. The unit is jacketed in a heat-insulating material in such a-waythat excessive heat'loss is obviated even when the unit is immersed in a refrigerated coagulating bath. The spinnerette is mounted upon a support, face upwards, in such a way that only the spinning face itself is exposed to the cooling effect of the spinning bath. The extruded solution, specifically a solutionof an acrylonitrile polymer, is coagulated, withdrawn directly from the spinnerette and directediin' a free, upward travel or direction to further operating treatments or steps, thereby eliminating completely-all guides and tension-causing-devices. The advantages of'this will be immediately apparent to those skilled in the art.

Another practical'advantage of the spinning device of this invention is the fact; that operation of the device is unaffected (that is, spinning'is not interrupted)- by sudden fluctuations in the level of the coagulating bath. This is in marked contrast to that which can and often does occur when a spinning device is designed sothat the face of the spinnerette is' in contact only 'with-the surface of the coagulating bath and extrusion of the spinning solution is downward" through thecoagulatingbath.

It also will-be notedfrom-the foregoing description of the device and-its use that the solution tube-spun ismaintained atanelevated temperature immediately prior to extrusion and, as" a' result, its viscosity is materially lessened and the solution will flow more rapidly through the openings in the spinnerette than otherwise would be possible with an unheated solution. By thus heating the solution immediately prior to extrusion and materially reducing its viscosity, a substantial reduction in the operating pressure, with obvious advantages, is eflected. Furthermore, by increasing the fluidity of the solution at the point of extrusion, the filamentary material can be pulled from the spinnerette at a greater speed, thereby increasing the amount of filament that can be produced from a particular unit. The practical advantages of such higher pullaway speeds will be immediately apparent to those skilled in the art.

The temperature to which the spinning solution is heated in the device of the present invention can be varied as desired or as conditions may require. The device is particularly useful in the spinning of a solution of a polymer or copolymer of acrylonitrile dissolved in a concentrated aqueous solution of a salt which yields highly hydrated ions in an aqueous solution, e. g., sodium thiocyanate, calcium thiocyanate, etc., as disclosed in, for example, Cresswell U. S. Patents 2,558,730, l, and -2, and Cresswell and Wizon U. 3. Patent 2,558,733. In the process there described, the solution of the acrylonitrile polymerization product is brought into contact, immediately after extrusion, with a liquid coagulant comprising water maintained at a temperature not exceeding C., e. g., C. to +5 C. When the spinning solution is extruded through the openings in the spinnerette and immediately brought into contact with such a cold liquid coagulant, the temperature to which the solution is heated in my new device immediately prior to extrusion ordinarily is within the range of 60 to 100 C. In the absence of suitable means for preheating the spinning solution immediately prior to extrusion, such as a device of the present invention, the viscosity of the solution Within the spinnerette is substantially increased by contact of the face of the spinnerette with the cold liquid coagulant, so that extrusion is very slow and pressure development is very substantially increased.

I claim:

1. A spinnerette assembly adapted to be immersed in a cold liquid coagulating bath, said assembly including a spinnerette; a spinnerette header comprising an elongated body member provided with a central duct for the passage of a viscous spinning solution to a spinnerette, said body member curving vertically upwards at its lower end so as to permit the vertically upward extrusion of said spinning solution and terminating at said lower end in a support for said spinnerette, and the upper and lower ends of saidelongated body member being in approximately the same vertical plane; means for detachably mounting said spinnerette, face upwards, upon said support, said means including a male threaded member and a female coupling each comprised of molded, heat-insulat' ing resin; walls defining a hollow heating unit surrounding said central duct, the said unit being rigidly attached and sealed to the main body portion of said central duct; an inlet conduit for introducing a hot fluid medium to said hollow heating unit through an inlet in the lower end of said elongated body member close to its lower extremity and an outlet conduit for withdrawing a hot fluid medium from said hollow heating unit through an outlet in the upper end of said body member close to its upper extremity, said inlet and outlet conduits being positioned closely, and rigidly attached, to the said elongated body member; and a jacket of heat-insulating material comprised of a main layer of foamed insulation, a protective layer of adhesive tape covering said main layer, and an outer layer comprised of synthetic resin which effectively seals the said main and protective layers against the entrance of moisture and, also, adds strength to the unit, said heat-insulating material surrounding said hollow heating unit and the aforesaid inlet and outlet conduits that are adjacent thereto.

2. A spinnerette assembly as in claim 1 wherein the main layer of foamed insulation comprises foam glass.

References Cited in the file of this patent UNITED STATES PATENTS 1,678,354 Richter July 24, 1928 2,485,958 Cresswell Oct. 25, 1949 2,698,459 Pedlow Jan. 4, 1955 2,732,585 Wicker Ian. 31, 1956 

